Vibration pickup device, vibration measurement device, measurement system, and measurement method

ABSTRACT

A vibration pickup device for measuring an electronic device that transmits sound to a user via vibration transmission by pressing a vibrating body held in a housing against a human ear includes a plate-shaped vibration transmission member and a vibration pickup joined to a portion of the vibration transmission member. The vibration transmission member is mountable on a peripheral portion of an artificial external ear canal, formed in an ear model unit modeled after a human ear, and includes a hole in communication with the artificial external ear canal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Japanese PatentApplication No. 2012-235030 filed Oct. 24, 2012, and Japanese PatentApplication No. 2013-042335 and Japanese Patent Application No.2013-042339 filed Mar. 4, 2013, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention is related to a vibration pickup device and avibration measurement device for measuring an amount of vibration by anelectronic device that is configured to transmit sound to a user viavibration transmission by pressing a vibrating body held in a housingagainst a human ear. The present invention also relates to a measurementsystem and a measurement method for measuring vibration of theelectronic device and to a measurement system and measurement method forevaluating the electronic device.

BACKGROUND

JP 2005-348193 A (PTL 1) discloses an electronic device, such as amobile phone or the like, that transmits air-conducted sound andbone-conducted sound to a user. As the air-conducted sound, PTL 1discloses a sound that is transmitted to the user's auditory nerve byair vibrations, caused by a vibrating object, that are transmittedthrough the external ear canal to the eardrum and cause the eardrum tovibrate. As the bone-conducted sound, PTL 1 discloses a sound that istransmitted to the user's auditory nerve through a portion of the user'sbody (such as the cartilage of the outer ear) that is contacting avibrating object.

In the telephone disclosed in PTL 1, a rectangular vibrating body,formed from a piezoelectric bimorph and a flexible substance, isattached to an outer surface of a housing via an elastic member. PTL 1also discloses that when voltage is applied to the piezoelectric bimorphin the vibrating body, the piezoelectric material expands and contractsin the longitudinal direction, causing the vibrating body to undergobending vibration. Air-conducted sound and bone-conducted sound aretransmitted to the user when the user touches the vibrating body to theauricle. The applicant has also developed a mobile phone that, unlikethe mobile phone disclosed in PTL 1, causes a panel, such as a displaypanel or protective panel disposed on a surface of the mobile phone, toundergo bending vibration due to a piezoelectric element, and thattransmits sound using air-conducted sound generated by the bendingvibration and vibration sound, which is a sound component due tovibration transmitted when the vibrating panel is pressed against ahuman ear.

CITATION LIST Patent Literature

PTL 1: JP 2005-348193 A

The inventor has also been involved in development of a mobile phonethat, unlike the mobile phone disclosed in PTL 1, transmits sound usingair-conducted sound, which is generated by vibrating a panel such as adisplay panel or protective panel disposed on a surface of the mobilephone, and vibration sound, which is a sound component due to vibrationtransmitted when the vibrating panel is pressed against a human ear. Inorder to appropriately evaluate an electronic device that transmits someform of sound by vibration, such as a telephone like the one in PTL 1,the mobile phone developed by the inventor, or the like, the inventorthen conceived of how it would be preferable to measure the degree ofthe sound pressure and the amount of vibration transmitted to a humanbody by vibration of the vibrating body with as close of anapproximation to a human body as possible. The following two methods ofmeasurement are general methods for measuring the amount of vibration.

The first method of measurement is to measure the amount of vibration asvoltage by pressing the vibrating body targeted for measurement againstan artificial mastoid, for bone conducted vibrator measurement, thatmechanically simulates the mastoid process behind the ear. The secondmethod of measurement is to measure the amount of vibration as voltageby pressing a vibration pickup, such as a piezoelectric accelerationpickup, against the vibrating body targeted for measurement.

The measured voltage obtained with the first method of measurement,however, is a voltage mechanically weighted for characteristics of ahuman body when the vibrating body is pressed against the mastoidprocess behind a human ear. This is not a voltage weighted forcharacteristics of vibration transmission when the vibrating body ispressed against a human ear. Furthermore, the measured voltage obtainedwith the second method of measurement measures the amount of vibrationof the vibrating body directly from the vibrating object. Similarly,this is not a voltage weighted for characteristics of vibrationtransmission to a human ear. Therefore, the amount of vibration that anelectronic device transmits to a human body cannot be accuratelyevaluated by measuring the amount of vibration of the vibrating bodywith the above methods of measurement. For these reasons, there is adesire for the development of a device that can measure the amount ofvibration weighted for characteristics of vibration transmission to ahuman ear.

For an electronic device provided with a vibrating body, such as apiezoelectric receiver, that transmits some form of sound by vibration,such as a telephone like the one in PTL 1, a mobile phone, or the like,there is a demand in managing device specifications to evaluate thedevice by testing the characteristics of the vibrating body at themanufacturing stage. Evaluation and specification management of anelectronic device provided with a vibrating body, however, has not beenconsidered whatsoever.

To cause a panel to undergo bending vibration due to a piezoelectricelement, it is assumed that one entire surface of the piezoelectricelement will be attached to the panel by an adhering member, such asdouble-sided tape, adhesive, or the like. In this case, it is alsoassumed that a buffer member will be provided between the piezoelectricelement and the panel. When the piezoelectric element is thus attachedto the panel, the vibration performance of the panel changes upon achange in the adhesive state between the panel and the piezoelectricelement or buffer member. For example, when the piezoelectric element isdriven continuously for a long period of time, it is thereforeenvisioned that the adhesive state of the piezoelectric element willchange, inhibiting the vibration performance that was supposed to beachieved. This vibration performance cannot be evaluated withoutlistening to the vibration sound transmitted when pressing an earagainst the panel, yet it is difficult for a person to listen tovibration sound continuously for several hours and evaluate slightchanges.

In order to satisfy the above-described demand, the present invention isto provide a vibration pickup device and a vibration measurement devicefor measuring an amount of vibration weighted for characteristics ofvibration transmission to a human ear, especially to the portionscentering on the cartilage of the ear.

The present invention is also to provide a measurement system and ameasurement method that allow for accurate evaluation and easyspecification management of an electronic device including a vibratingbody that transmits sound by vibration transmission.

The present invention is also to provide a measurement system and ameasurement method that allow for easy and accurate evaluation of anelectronic device that transmits sound to a user based on vibration of avibrating body.

SUMMARY

A vibration pickup device according to an aspect of the presentinvention is a vibration pickup device for measuring an electronicdevice that transmits sound to a user via vibration transmission bypressing a vibrating body held in a housing against a human ear, thevibration pickup device including:

a plate-shaped vibration transmission member and a vibration pickupjoined to a portion of the vibration transmission member, such that thevibration transmission member is mountable on a peripheral portion of anartificial external ear canal and includes a hole in communication withthe artificial external ear canal, and the artificial external ear canalis formed in an ear model unit modeled after a human ear.

The hole in the vibration transmission member may have a diameter of 5mm to 18 mm.

The vibration transmission member may be ring-shaped.

The vibration transmission member may have an external diameter 6 mm to12 mm greater than the diameter of the hole.

The vibration pickup may be a piezoelectric acceleration pickup.

A vibration measurement device according to another aspect of thepresent invention is a vibration measurement device for measuring anelectronic device that transmits sound to a user via vibrationtransmission by pressing a vibrating body held in a housing against ahuman ear, the vibration measurement device including:

an ear model unit modeled after a human ear, and the above vibrationpickup device, such that in the vibration pickup device, the hole formedin the vibration transmission member is in communication with theartificial external ear canal, and the vibration transmission member ismounted on a peripheral portion of the artificial external ear canalformed in the ear model unit.

The ear model unit may include a mounting portion that detachably mountsthe vibration pickup device in a predetermined positional relationship.

The mounting portion may include an insertion holder that insertablyholds the vibration transmission member and a positioning portion thatpositions the vibration pickup with respect to the ear model unit.

A human head model may be further included, such that the ear model unitis an artificial ear forming part of the head model and is detachablefrom the head model.

The ear model unit may include an ear model and an artificial externalear canal unit joined to the ear model, and

the artificial external ear canal may be formed in the artificialexternal ear canal unit.

The length of the artificial external ear canal to the hole formed inthe vibration transmission member of the vibration pickup device may befrom 8 mm to 30 mm.

The ear model unit may be formed from material conforming to IEC60318-7.

The ear model unit may further include a microphone device that measuressound pressure of sound propagating through the artificial external earcanal.

The microphone device may include a microphone held in a tube memberextending from an outer wall of the artificial external ear canal.

The microphone device may include a microphone disposed in a floatingstate with respect to an outer wall of the artificial external earcanal.

A measurement system according to yet another aspect of the presentinvention is a measurement system for measuring vibration of anelectronic device that transmits sound to a user via vibrationtransmission by pressing a vibrating body held in a housing against ahuman ear, the measurement system including: a signal output unitconfigured to output a test signal that vibrates the vibrating body; astorage configured to store a first test signal corresponding to apredetermined test sound; a generation unit configured to generate asecond test signal corresponding to a different test sound than thepredetermined test sound; and a controller configured to store vibrationof the vibrating body vibrated by the first test signal or the secondtest signal and to measure the stored vibration.

A measurement system according to yet another aspect of the presentinvention is a measurement system for evaluating an electronic devicethat transmits sound to a user via vibration transmission by pressing avibrating body held in a housing against a human ear, the measurementsystem including:

a test signal output unit configured to output a test signal thatvibrates the vibrating body;

a vibration detector configured to detect vibration of the vibratingbody; and

a measurement unit configured to analyze vibration of the vibrating bodybased on output of the vibration detector, such that

the measurement unit vibrates the vibrating body by outputting the testsignal from the test signal output unit repeatedly a designated numberof iterations across a predetermined frequency range and analyzesvariation in a frequency characteristic of the vibration based on outputof the vibration detector during sequential repetition of the testsignal.

According to the present invention, a vibration pickup device and avibration measurement device for measuring an amount of vibrationweighted for characteristics of vibration transmission to a human earmay be provided.

Furthermore, according to the present invention, accurate evaluation maybe made and specification management is facilitated for an electronicdevice including a vibrating body that transmits sound by vibrationtransmission.

According to the present invention, a measurement system and ameasurement method may be provided, that allow for easy and accurateevaluation of an electronic device that transmits sound to a user basedon vibration of a vibrating body that is held in a housing and pressedagainst a human ear.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described below with reference tothe accompanying drawings, wherein:

FIG. 1 schematically illustrates the structure of a measurement systemthat uses a vibration measurement device according to Embodiment 1 ofthe present invention;

FIG. 2 is a plan view illustrating an example of an electronic devicetargeted for measurement;

FIGS. 3A and 3B illustrate the structure of the vibration pickup devicein FIG. 1;

FIGS. 4A and 4B illustrate details on the vibration measurement head inFIG. 1;

FIG. 5 is a functional block diagram of a section of the measurementsystem in FIG. 1;

FIG. 6 illustrates the ear model unit in FIG. 1;

FIG. 7 illustrates an example of measurement results by the vibrationpickup in a vibration experiment on the ear model unit in FIG. 6;

FIG. 8 illustrates an example of measurement results by a laserdisplacement gauge in a vibration experiment on the ear model unit inFIG. 6;

FIGS. 9A and 9B illustrate the structure of a section of a vibrationmeasurement head according to Embodiment 2 of the present invention;

FIG. 10 is a functional block diagram of a section of a measurementsystem according to Embodiment 3 of the present invention;

FIG. 11 illustrates an example of a cue signal and a test signal;

FIG. 12 is a modification to the functional block diagram of a sectionof the measurement system;

FIG. 13 illustrates an example of an evaluation application screen;

FIG. 14 illustrates an example of measurement results;

FIG. 15 is a functional block diagram of a section of a measurementsystem according to Embodiment 4 of the present invention;

FIG. 16 illustrates an example of a setting screen for an aging test bya measurement system according to Embodiment 5 of the present invention;

FIG. 17 illustrates an example of displaying the frequencycharacteristic resulting from the aging test;

FIG. 18 illustrates an example of displaying the output variation, atmonitored frequencies, resulting from the aging test;

FIG. 19 illustrates an example of a setting screen of a test toreproduce a problem;

FIG. 20 illustrates the time lag between the output of test sound andthe start of playback in the test to reproduce a problem;

FIG. 21 schematically illustrates the structure of a measurement systemaccording to Embodiment 6 of the present invention; and

FIGS. 22A and 22B are detailed diagrams of the measurement system inFIG. 21.

DETAILED DESCRIPTION

The following describes embodiments of the present invention withreference to the drawings.

Embodiment 1

FIG. 1 schematically illustrates the structure of a measurement systemthat uses a vibration measurement device according to Embodiment 1 ofthe present invention. A measurement system (measurement device) 10according to the present embodiment is for evaluating an electronicdevice 100, which includes a vibrating body and is targeted formeasurement. The measurement device 10 is provided with an electronicdevice mounting portion 20 and a measurement unit 200 connected to theelectronic device mounting portion 20 and the electronic device 100. Inthe measurement device 10, the electronic device mounting portion 20 andthe measurement unit 200 may be formed integrally, or the electronicdevice mounting portion 20 and the measurement unit 200 may be separateand appropriately connected. The electronic device mounting portion 20is provided with a vibration measurement device (vibration measurementhead) 40 supported by a base 30 and a holder 70 that holds theelectronic device 100 targeted for measurement. The measurement unit 200may be disposed on the base 30 or may be disposed separately from thebase 30. In the explanation below, the electronic device 100 is assumedto be a mobile phone, such as a smartphone, that includes a rectangularpanel 102 larger than a human ear on a surface of a rectangular housing101, as illustrated in the plan view in FIG. 2, and that vibrates withthe panel 102 as a vibrating body. First, the vibration measurement head40 is described.

The vibration measurement head 40 is provided with an ear model unit 50and a vibration pickup device (vibration detector) 55. The ear modelunit 50 is modeled after a human ear and includes an ear model 51 andartificial external ear canal unit 52 joined to the ear model 51. Theear model unit 50 in FIG. 1 corresponds to the left ear of a human yetmay be the left ear instead. An artificial external ear canal 53 isformed in the central region of the artificial external ear canal unit52. The artificial external ear canal 53 is formed with a hole diameterof 5 mm to 10 mm, which is the average diameter of the human externalacoustic pore. The ear model unit 50 is detachably supported on the base30 via a support member 54 at the periphery of the artificial externalear canal unit 52. The artificial external ear canal unit 52 may beattached to the ear model unit 50 or may be produced integrally with theear model unit 50 with a single mold.

The ear model unit 50 is made from similar material to the material ofan average ear model used in, for example, a manikin such as a Head AndTorso Simulator (HATS), Knowles Electronic Manikin for Acoustic Research(KEMAR), or the like, such as material conforming to IEC 60318-7. Thismaterial may, for example, be formed with a material such as rubberhaving a hardness of 35 to 55. The hardness of rubber may, for example,be measured in conformity with International Rubber Hardness Degrees(IRHD/M) conforming to JIS K 6253, ISO 48, or the like. As a hardnessmeasurement device, a fully automatic IRHD/M micro-size internationalrubber hardness gauge GS680 by Teclock Corporation may suitably be used.Note that taking the variation in ear hardness due to age into account,as a rule of thumb, approximately two or three types of the ear modelunit 50 with a different hardness are preferably prepared and usedinterchangeably.

The thickness of the artificial external ear canal unit 52, i.e. thelength of the artificial external ear canal 53, corresponds to thelength up to the human eardrum (cochlea) and for example is suitably setin a range of 5 mm to 50 mm, preferably 8 mm to 30 mm. In the presentembodiment, the length of the artificial external ear canal 53 isapproximately 30 mm.

The vibration pickup device 55 detects the amount of vibrationtransmitted through the external ear canal unit 52 when the vibratingpanel 102 is placed against the ear model unit 50. In other words, thevibration pickup device 55 detects the amount of vibration correspondingto the bone conducted component that is heard without passing throughthe eardrum when the panel 102 is pressed against a human ear andvibration of the panel 102 directly vibrates the inner ear. Asillustrated by the plan view in FIG. 3A and the front view in FIG. 3B,the vibration pickup device 55 includes a plate-shaped vibrationtransmission member 56 and one vibration pickup 57 joined to a portionof one face of the vibration transmission member 56. The vibrationtransmission member 56 includes a hole 56 a with a diameter nearly equalto the hole diameter of the artificial external ear canal 53, such as adiameter of 7 mm, 7.5 mm, or 15 mm. In the present embodiment, the otherface of the vibration transmission member 56 is adhered to the end faceof the artificial external ear canal unit 52 at the opposite side fromthe ear model 51, so that the hole 56 a is in communication with theartificial external ear canal 53. The vibration pickup 57 is, forexample, joined to one face of the vibration transmission member 56 withgrease or the like therebetween. The vibration pickup 57 is connected tothe measurement unit 200. The vibration pickup device 55 is furtherdescribed below.

Furthermore, the vibration measurement head 40 according to the presentinvention is provided with a microphone device (sound pressuremeasurement unit) 60 for measuring the sound pressure of soundpropagating through the artificial external ear canal 53. As illustratedby the plan view in FIG. 4A from the side of the base 30 and thecross-sectional view in FIG. 4B along the b-b line in FIG. 4A, themicrophone device 60 includes a tube member 61 and microphone 62 held bythe tube member 61. The tube member 61 extends from the outer wall(peripheral wall of the hole) of the artificial external ear canal 53through the hole 56 a of the vibration transmission member 56 in thevibration pickup device 55. The microphone 62 is, for example,configured using a measurement capacitor microphone that has a lowself-noise level and that has flat output characteristics in themeasurement frequency range of the electronic device 100. As themicrophone 62, for example the capacitor microphone UC-53A by RionCorporation may be used. The microphone 62 is disposed so that the soundpressure detection face nearly matches the end face of the artificialexternal ear canal unit 52. The microphone 62 may, for example, besupported by the artificial external ear canal unit 52 or the base 30and disposed in a floating state with respect to the outer wall of theartificial external ear canal 53. In FIG. 4A, the artificial externalear canal unit 52 is rectangular, yet the artificial external ear canalunit 52 may be any shape. The microphone 62 is connected to themeasurement unit 200.

Next, the holder 70 is described. If the electronic device 100 is amobile phone having a rectangular shape in plan view, such as asmartphone, then when a person holds a mobile phone in one hand andpresses the mobile phone against his or her ear, both sides of themobile phone are normally supported by the hand. The pressing force andcontact position of the mobile phone against the ear differ for eachperson (user) and also vary during use. In the present embodiment, theelectronic device 100 is held so as to simulate such a form of using themobile phone.

Therefore, the holder 70 is provided with a support 71 that supportsboth sides of the electronic device 100. The support 71 is attached toone end of an arm 72 so as to be rotatable about an axis y1, which isparallel to the y-axis, in a direction to press the electronic device100 against the ear model unit 50. The other end of the arm 72 is joinedto a movement adjuster 73 provided on the base 30. The movement adjuster73 can adjust movement of the arm 72 in a vertical direction x1 of theelectronic device 100 supported by the support 71, the direction x1being parallel to the x-axis that is orthogonal to the y-axis, and in adirection z1 that presses the electronic device 100 against the earmodel unit 50, the direction z1 being parallel to the z-axis that isorthogonal to the y-axis and the x-axis.

In this way, the pressing force of the electronic device 100, which issupported by the support 71, against the ear model unit 50 of thevibrating body (panel 102) is adjusted by rotating the support 71 aboutthe axis y1 or by moving the arm 72 in the z1 direction. In the presentembodiment, the pressing force is adjusted in a range of 0 N to 10 N,preferably a range of 3 N to 8 N.

The reason for the range from 0 N to 10 N is to allow for measurementover a range that is sufficiently wider than the pressing force that isenvisioned when a human presses the electronic device against an ear,for example to converse. The case of 0 N may, for example, include notonly the case of contacting without pressing against the ear model unit50, but also the case of holding the electronic device 100 at a distancefrom the ear model unit 50 in increments of 1 mm to 1 cm and measuringat each distance. This approach also allows for measurement with themicrophone 62 of the damping of air-conducted sound due to distance,thus making the measurement device more convenient. The range of 3 N to8 N is assumed to be the range of the average force with which a personwith normal hearing presses an ordinary speaker against an ear toconverse. Differences may exist by race or gender, yet what matters isthat in an electronic device such as an ordinary mobile phone, asmartphone equipped with an ordinary speaker, or the like, it ispreferable to able to measure the vibration sound and air-conductedsound for the pressing force that a user regularly applies.

By adjusting movement of the arm 72 in the x1 direction, the contactposition of the electronic device 100 with respect to the ear model unit50 can be adjusted so that, for example, the panel 102 that is anexample of the vibrating body covers nearly the entire ear model unit50, or so that the panel 102 covers a portion of the ear model unit 50,as illustrated in FIG. 1. A configuration may also be adopted to allowfor adjustment of the electronic device 100 to a variety of contactpositions with respect to the ear model unit 50 by making movement ofthe arm 72 adjustable in a direction parallel to the y-axis, or bymaking the arm 72 rotatable about an axis parallel to the x-axis or thez-axis. The vibrating body is of course not limited to an object like apanel that widely covers the ear, and for example an electronic devicehaving a protrusion or corner that transmits vibration to only a portionof the ear model unit 50, such as the tragus, may be targeted formeasurement in the present invention.

FIG. 5 is a functional block diagram of a section of the measurementdevice 10 according to the present embodiment. The vibration pickup 57and the microphone 62 are connected to the measurement unit 200, asdescribed above. Based on output of the vibration pickup 57 and themicrophone 62, the measurement unit 200 measures the amount ofvibration, via the artificial external ear canal unit 52, and the soundpressure, via the artificial external ear canal 53, due to theelectronic device 100. The measurement unit 200 also measures anauditory sensation based on the measured amount of vibration and soundpressure. These measurement results are output from an output unit suchas a display, a printer, a storage, or the like and provided forevaluation of the electronic device 100.

The vibration pickup device 55 is now described in greater detail. FIG.6 is a plan view, from the base 30 side, of the ear model unit 50 in thevibration measurement head 40 of FIG. 1, with the vibration pickupdevice 55 removed. For the sake of convenience, FIG. 6 illustrates thearea surrounding the hole in the artificial external ear canal 53divided into eight areas A1 to A8. The ear model 51 in FIG. 1 is a modelof a human left ear. In FIG. 6, area A4 mainly corresponds to the upperportion of the antitragus, and area A5 mainly corresponds to the tragusside.

FIGS. 7 and 8 illustrate examples of measurement results for a vibrationtest on the ear model unit 50 in FIG. 6. The measurement results in FIG.7 depict the amount of vibration for each of areas A1 to A8 in the earmodel unit 50 in FIG. 6 when the ear model unit 50 was set on the base30, the electronic device 100 was set in the holder 70, the panel 102was pressed against the ear model unit 50, and in this state, the panel102 was vibrated in a frequency range from 500 Hz to 3.5 kHz. The amountof vibration was measured by adhering one vibration pickup sequentiallyto the areas A1 to A8 via double-sided tape. In FIG. 7, A0 representsthe result of measuring the amount of vibration of the panel 102 in theelectronic device 100 with the same vibration pickup. The measurementresults in FIG. 8 were obtained by using a laser displacement gauge tomeasure the form of vibration of the end face of the ear model unit 50at the base 30 side upon vibrating the panel 102 of the electronicdevice 100 at a predetermined frequency (for example, 2000 Hz) under thesame measurement conditions as FIG. 7.

As is clear from FIG. 7, the frequency characteristic of vibrationdetected for each of the areas A1 to A8 differs from the frequencycharacteristic A0 of vibration of the panel 102. Therefore, designatingone area and adhering one vibration pickup decreases the detectionaccuracy of the vibration component transmitted to the auditory nerve.Adhering a vibration pickup to each of the plurality of areas in orderto increase the detection accuracy, however, reduces the processingspeed of the measurement device due to an increase in processing signalsand also leads to a higher cost of the measurement device. Along withincreased weight of the vibration pickups, there is also a risk ofdecreased detection accuracy of subtle vibration.

Furthermore, as is clear from FIG. 8, the amount of displacement of theear model unit 50 due to vibration of the panel 102 in the electronicdevice 100 predominates in a line, along the tragus of the ear model 51,that includes areas A3, A5, and A8. Moreover, each of the areas A1 to A8is not displaced uniformly, but rather the areas corresponding to theperipheral portion of the artificial external ear canal 53 are largelydisplaced.

In light of the above measurement results, the vibration pickup device55 according to the present embodiment includes the plate-shapedvibration transmission member 56 and one vibration pickup 57 joined to aportion of one face of the vibration transmission member 56. Thevibration transmission member 56 includes the hole 56 a with a diameterequal to or greater than that of the artificial external ear canal 53.In the vibration pickup device 55, the face of the vibrationtransmission member 56 to which the vibration pickup 57 is not joined isattached, by adhering or the like, to the artificial external ear canalunit 52 around the artificial external ear canal 53, so that the hole 56a of the vibration transmission member 56 is in communication with theartificial external ear canal 53 without blocking the artificialexternal ear canal 53.

The vibration transmission member 56 is formed from material with goodvibration transmission efficiency. For example, a metal or an alloy,such as steel, SUS, brass, aluminum or titanium, or plastic or the likemay be used, yet in terms of detection sensitivity, a lightweightmaterial is preferable. The vibration transmission member 56 may berectangular, such as a square washer, yet in the present embodiment, aring shape such as a round washer is adopted, since the amount ofdisplacement of the ear model unit 50 is large at the peripheral portionof the artificial external ear canal 53, as illustrated in FIG. 8. Thering shape may, for example, have a diameter of approximately 20 mm to70 mm, which is the diameter of approximately 10 mm to 30 mm of the hole56 a with the addition of twice the ring width of 5 mm to 20 mm. Thethickness of the vibration transmission member 56 is set appropriatelyin accordance with material strength or the like. In greater detail, a0.1 mm thick SUS plate with an outer diameter of 35 mm, a diameter of 25mm for the hole 56 a, and a width of 5 mm may be used.

The vibration pickup 57 has flat output characteristics in themeasurement frequency range (for example, 0.1 kHz to 30 kHz) of theelectronic device 100, and an existing small vibration pickup that islightweight and can accurately measure subtle vibration may be used. Anexample of such a vibration pickup is a piezoelectric accelerationpickup, such as the vibration pickup PV-08A by Rion Corporation or thelike. In the present embodiment, a piezoelectric acceleration pickup isused as the vibration pickup 57, and the piezoelectric accelerationpickup is joined to the vibration transmission member 56 via a joiningmember, such as grease or the like, an instant adhesive such as AronAlpha (registered trademark), or the like. As illustrated in FIGS. 7 and8, the vibration of the panel 102 in the electronic device 100 is easilytransmitted to areas A3, A5, and A8 of the ear model unit 50.Accordingly, the vibration pickup device 55 is preferably mounted on theartificial external ear canal unit 52 so that the vibration pickup 57 isopposite one of the areas A3, A5, and A8, for example area A5, or so asto straddle both areas A5 and A8, with the vibration transmission member56 therebetween. FIGS. 4A and 4B illustrates an example of the vibrationpickup device 55 being mounted so that the vibration pickup 57 isopposite area A5.

The measurement device 10 according to the present embodiment allows forthe vibration that propagates to the peripheral portion of theartificial external ear canal 53 to be transmitted by the vibrationpickup device 55 via the vibration transmission member 56 to onevibration pickup 57 and detected. In this way, the vibration pickupdevice 55 can be reduced in weight, and vibration over a large area inthe peripheral portion of the artificial external ear canal 53 can bedetected. Accordingly, a detection signal with good S/N can be obtainedat a high level from the vibration pickup 57, thus allowing for highlyaccurate detection of the vibration component transmitted to theauditory nerve.

Moreover, the measurement device 10 according to the present embodimentcan measure the vibration level weighted for characteristics ofvibration transmission to a human ear, hence allowing for accurateevaluation of the electronic device 100. At the same time as thevibration level, the sound pressure can also be measured via theartificial external ear canal 53, allowing for measurement of anauditory sensation level that combines the vibration level, whichcorresponds to the amount of vibration transmission to the human ear,and the sound pressure level, which corresponds to the air-conductedsound. Hence, the electronic device 100 can be evaluated in greaterdetail. Furthermore, the pressing force on the ear model unit 50 of theelectronic device 100 can be adjusted, as can the contact position, thusallowing for a variety of forms of evaluating the electronic device 100.

Embodiment 2

FIGS. 9A and 9B illustrate the structure of a section of a vibrationmeasurement head according to Embodiment 2 of the present invention.FIG. 9A is a partial cross-section of the artificial external ear canalunit 52 before mounting of the vibration pickup device 55, and FIG. 9Bis a bottom view of the artificial external ear canal unit 52 aftermounting of the vibration pickup device 55. A vibration measurement head41 according to the present embodiment has the structure of thevibration measurement head 40 according to Embodiment 1, with theinclusion of a mounting portion 42, at the end of the artificialexternal ear canal unit 52 opposite the ear model 51 (at the bottomside), for removably mounting the vibration pickup device 55 in apredetermined positional relationship. The mounting portion 42 includesan insertion holder 43 for the vibration transmission member 56 and apositioning portion 44 for the vibration pickup 57. The insertion holder43 includes an opening 45, concentric and continuous with the artificialexternal ear canal 53, and a large-diameter space 46 in communicationwith the opening 45. The positioning portion 44 is formed by cutting theinsertion holder 43 so that the vibration pickup 57 protrudes from apredetermined area of the insertion holder 43, for example an areacorresponding to area A5 in FIG. 6. The cutout for the positioningportion 44 may be in communication with the opening 45 as well.

With the vibration measurement head 41 according to the presentembodiment, when mounting the vibration pickup device 55 onto themounting portion 42 of the ear model unit 50, the vibration transmissionmember 56 is inserted into the insertion holder 43 while widening theartificial external ear canal unit 52 at the bottom side of theinsertion holder 43 to an extent not causing plastic deformation, sothat the vibration transmission member 56 is held in the large-diameterspace 46, with the vibration pickup 57 protruding from the positioningportion 44. In this way, in the vibration pickup device 55, the hole 56a of the vibration transmission member 56 is in nearly concentriccommunication with the artificial external ear canal 53 and the opening45, and the vibration transmission member 56 is held by being embeddedin the large-diameter space 46 in a predetermined positionalrelationship with respect to the ear model unit 50. Furthermore, thevibration pickup device 55 can be removed from the mounting portion 42of the ear model unit 50 by expanding the artificial external ear canalunit 52 at the bottom side of the insertion holder 43 to an extent notcausing plastic deformation and pulling the vibration transmissionmember 56 out from the insertion holder 43. Replacement of the ear modelunit 50 or the vibration pickup device 55 is thus facilitated. The othereffects are similar to those of Embodiment 1.

Embodiment 3

Next, a measurement system according to Embodiment 3 of the presentinvention is described. The measurement system according to Embodiment 3adopts a different structure for the measurement unit 200 within thestructure of the measurement device 10 according to Embodiment 1. FIG.10 is a functional block diagram illustrating the structure of a sectionof the measurement unit 200 in the measurement system (measurementdevice) according to Embodiment 3. The measurement unit 200 includes asensitivity adjuster 300, signal processor 400, personal computer (PC)500, and printer 600.

Output of the vibration pickup 57 and the microphone 62 is provided tothe sensitivity adjuster 300. The sensitivity adjuster 300 includes avariable gain amplifier circuit 301 that adjusts the amplitude of theoutput of the vibration pickup 57 and a variable gain amplifier circuit302 that adjusts the amplitude of the output of the microphone 62. Thevariable gain amplifier circuits 301 and 302 independently adjust theamplitude of analog input signals, corresponding to the respectivecircuits, to a required amplitude either manually or automatically.Error in the sensitivity of the vibration pickup 57 and the sensitivityof the microphone 62 is thus corrected. Note that the variable gainamplifier circuits 301 and 302 are configured to allow for adjustment ofthe amplitude of the input signals over a range of, for example, ±50 dB.Output of the sensitivity adjuster 300 is provided to the signalprocessor 400.

The signal processor 400 includes an A/D converter 410, frequencycharacteristic adjuster 420, phase adjuster 430, output combiner 440,frequency analyzer 450, storage 460, acoustic signal output unit 480,and signal processing controller 470. The A/D converter 410 includes anA/D conversion circuit (A/D) 411 that converts the output of thevariable gain amplifier circuit 301 into a digital signal and an A/Dconversion circuit (A/D) 412 that converts the output of the variablegain amplifier circuit 302 into a digital signal. The A/D conversioncircuits 411 and 412 are, for example, 16 bits or more and can support96 dB or more by dynamic range conversion. The A/D conversion circuits411 and 412 may also be configured so that the dynamic range ischangeable. Output of the A/D converter 410 is provided to the frequencycharacteristic adjuster 420.

The frequency characteristic adjuster 420 includes an equalizer (EQ) 421that adjusts the frequency characteristic of the detection signal fromthe vibration pickup 57, i.e. the output of the A/D conversion circuit411, and an equalizer (EQ) 422 that adjusts the frequency characteristicof the detection signal from the microphone 62, i.e. the output of theA/D conversion circuit 412. The equalizers 421 and 422 independentlyadjust the frequency characteristic of the respective input signals to afrequency characteristic near the auditory sensation of the human bodyeither manually or automatically. The equalizers 421 and 422 may, forexample, be configured with a graphical equalizer having a plurality ofbands, a low pass filter, a high pass filter, or the like. Output of thefrequency characteristic adjuster 420 is provided to the phase adjuster430.

The phase adjuster 430 includes a variable delay circuit 431 thatadjusts the phase of the detection signal from the vibration pickup 57,i.e. the output of the equalizer 421. Since the speed of soundtransmitted through the material of the ear model unit 50 is not exactlythe same as the speed of sound transmitted through human muscle or bone,it is assumed that the phase relationship between the output of thevibration pickup 57 and the output of the microphone 62 will be shiftedgreatly from that of a human ear, particularly at high frequencies. Ifthe phase relationship between the output of the vibration pickup 57 andthe output of the microphone 62 thus shifts greatly, then when combiningthe two outputs with the below-described output combiner 440, amplitudepeaks and dips may appear at different times than in actuality, and thecombined output may be amplified or diminished. Therefore, in accordancewith the measurement frequency range of the electronic device 100targeted for measurement, the phase of the detection signal from thevibration pickup 57, which is the output of the equalizer 421, is madeadjustable over a predetermined range by the variable delay circuit 431.

For example, in the case of the measurement frequency range of theelectronic device 100 being from 100 Hz to 10 kHz, the phase of thedetection signal from the vibration pickup 57 is adjusted by thevariable delay circuit 431 over a range of approximately ±10 ms(corresponding to ±100 Hz) at least in increments smaller than 0.1 ms(corresponding to 10 kHz), such as increments of 0.04 μs. In the case ofa human ear as well, a phase shift occurs between bone-conducted sound(vibration transmission component) and air-conducted sound(air-conducted component). Therefore, phase adjustment by the variabledelay circuit 431 is not for matching the phase of the detection signalsfrom the vibration pickup 57 and the microphone 62, but rather formatching the phase of these detection signals to the actual auditorysensation by the ear. Output of the phase adjuster 430 is provided tothe output combiner 440.

The output combiner 440 combines the detection signal from the vibrationpickup 57, after phase adjustment by the variable delay circuit 431,with the detection signal, from the microphone 62, that has passedthrough the phase adjuster 430. It is thus enabled to approximate thehuman body in obtaining sensory sound pressure that combines the amountof vibration and the sound pressure, i.e. the vibration transmissioncomponent and air-conducted component, transmitted by vibration of theelectronic device 100 targeted for measurement. The combined output ofthe output combiner 440 is provided to the frequency analyzer 450. Thecombined output of the output combiner 33 is also provided to the signalprocessing controller 470, along with the output of the vibration pickup57, for which phase was adjusted, and the output of the microphone 62.Operations by the signal processing controller 470 are described below.

The frequency analyzer 450 includes a Fast Fourier Transform (FFT) 451that performs frequency analysis on the combined output of the outputcombiner 440. In this way, power spectrum data corresponding to thesensory sound pressure, in which the vibration transmission componentand the air-conducted component are combined, are obtained from the FFT451.

Furthermore, the frequency analyzer 450 is provided with FFTs 452 and453 that perform frequency analysis on the signals before combination bythe output combiner 440, i.e. on the detection signal, from thevibration pickup 57, that has passed through the phase adjuster 430 andthe detection signal from the microphone 62. In this way, power spectrumdata corresponding to the vibration transmission component are obtainedfrom the FFT 452, and power spectrum data corresponding to theair-conducted component are obtained from the FFT 453.

In the FFTs 451 to 453, analysis points are set for the frequencycomponent (power spectrum) in correspondence with the measurementfrequency range of the electronic device 100. For example, when themeasurement frequency range of the electronic device 100 is 100 Hz to 10kHz, analysis points are set so as to analyze the frequency component ateach point when dividing the interval in a logarithmic graph of themeasurement frequency range into 100 to 2000 equal portions.

The output of the FFTs 451 to 453 is stored in the storage 460. Thestorage 460 has the capacity of at least a double buffer that can storea plurality of analysis data sets (power spectrum data) for each of theFFTs 451 to 453. The storage 460 is configured to always allow fortransmission of the latest data upon a data transmission request fromthe below-described PC 500. A configuration may be adopted for output ofthe FFTs 451 to 453 to be input to the signal processing controller 470.Operations by the signal processing controller 470 for this case aredescribed below. A double buffer configuration need not be adopted ifthe analysis is not performed in real time but rather after recording.

The acoustic signal output unit 480 is configured so that an externallyconnected device, such as headphones, can be connected detachably. Viathe signal processing controller 470, the detection signal from thevibration pickup 57 or the detection signal from the microphone 62 inputinto the output combiner 440, or the combination by the output combiner440 of these detection signals, is selected and provided to the acousticsignal output unit 480. After appropriately adjusting the frequencycharacteristic of the input data with an equalizer or the like, theacoustic signal output unit 480 performs D/A conversion to an analogacoustic signal and outputs the result.

Furthermore, the signal processor 400 includes a test signal output unit495. Based on control by the signal processing controller 470, the testsignal output unit 495 vibrates the panel 102 of the electronic device100 and outputs a test signal for evaluating the electronic device 100.The test signal output unit 495 includes a test signal storage 496, atest signal generator 497, and an output adjuster 498. The test signaloutput unit 495 corresponds to the “signal output unit” in the presentembodiment.

The test signal storage 496 stores a test signal corresponding to apredetermined test sound. The predetermined test signal is, for example,a WAV file (audio data). The test signal storage 496 is preferablyconfigured to selectively read a plurality of WAV files. Each WAV filestored in the test signal storage 496 is, for example, copied from arecording medium or downloaded over a network and stored. The testsignal storage 496 corresponds to the “storage” in the presentembodiment.

The test signal generator 497 generates a test signal corresponding to adifferent test sound than the test sound corresponding to the testsignal stored in the test signal storage 496. The test signal generator497 is preferably configured to allow for selective generation andoutput of a signal corresponding to a pure tone composed of a singlefrequency sine wave (pure tone signal), a signal corresponding to a puretone sweep in which the frequency sequentially changes across apredetermined frequency range from low frequency to high frequency orhigh frequency to low frequency (pure tone sweep signal), and a signalthat is composed of a plurality of sine wave signals of differentfrequencies and that corresponds to sound in which a plurality of puretones are superimposed (multi-sine wave signal). The predeterminedfrequency range of the pure tone sweep signal may be appropriately setover a wide range that includes audible frequencies. The amplitude atthe sequential frequencies in the pure tone sweep signal is preferablythe same. The amplitude of each sine wave in the multi-sine wave signalis also preferably the same. The test signal generator 497 correspondsto the “generation unit” in the present embodiment.

The output adjuster 498 adds a signal corresponding to a cue sound (cuesignal) for the start of the test sound to each of the test signalsoutput by the test signal generator 497 and the test signal storage 496and outputs the result. FIG. 11 illustrates an example of a cue signaland a test signal. In FIG. 11, the horizontal axis is the time axis, anda cue signal SG60 followed by a test signal SG62 are illustrated. Thecue signal SG60 is a signal that can be detected in the time domain. Thecue signal SG60 is, for example, one or a plurality of sound signals ofa predetermined sound pressure. Each signal included in the cue signalSG60 may be a pure tone of a predetermined frequency or may be soundcomposed of a plurality of pure tones with different frequencies. Thefrequency of the sounds may be the same or different. The intervalbetween the cue signal SG60 and the test signal SG62 and the duration ofeach of these signals may be set freely.

In accordance with the signal format of external input to the electronicdevice 100 targeted for measurement, the output adjuster 498 convertsthe test signal to which the cue signal has been added to apredetermined signal format, such as conversion to an analog signal. Inthe case of the electronic device 100 being a mobile phone, the testsignal output unit 495 may output a signal encoded in accordance withstandards such as 3GPP (3GPP TS26.131/132), VoLTE, or the like. The testsignal output unit 495 provides the encoded signal to an external inputterminal 105 of the electronic device 100 via a connection cable 511 foran interface such as USB. In the electronic device 100, the signalprovided to the external input terminal 105 is decoded and provided to apiezoelectric element attached to the panel 102. The piezoelectricelement is driven, and the panel 102 vibrates.

Alternatively, as illustrated in FIG. 12, instead of the connectioncable 511, the measurement unit 200 may be configured so that atransmitter 511 t encodes the cue signal and test signal output by thetest signal output unit 495 and wirelessly transmits the result, and sothat a receiver 511 r receives and decodes the transmission signal fromthe transmitter 511 t, providing the result to the external inputterminal 105 of the electronic device 100. The configuration in FIG. 12other than the transmitter Slit and the receiver 511 r is the same as inFIG. 5. With this configuration, when the electronic device 100 is amobile phone such as a smartphone, data loss via wireless communicationcan be simulated, thus allowing for more accurate measurement.

The signal processing controller 470 is connected to the PC 500 via aconnection cable 510 for an interface such as USB, RS-232C, SCSI, PCcard, or the like. Based on commands from the PC 500, the signalprocessing controller 470 controls operations of each portion of thesignal processor 400. The sensitivity adjuster 300 and the signalprocessor 400 may be configured as software executed on any suitableprocessor, such as a central processing unit (CPU), or may be configuredwith a digital signal processor (DSP).

The PC 500 includes a memory 501 or the like that stores an evaluationapplication, a variety of data, and the like for the measurement system(measurement device) 10 to evaluate the electronic device 100. Thememory 501 may be internal memory or external memory. The evaluationapplication is placed in the memory 501 by copying from a CD-ROM,downloading over a network, or the like. The PC 500 for example displaysan application screen on a display 520 based on the evaluationapplication. Based on information input via the application screen, thePC 500 transmits a command to the signal processor 400. The PC 500 alsoreceives a command acknowledgment and data from the signal processor400, and based on the received data, executes predetermined processingand displays the measurement results on the application screen. Asnecessary, the PC 500 also outputs the measurement results to theprinter 600 to print the measurement results.

The measurement system (measurement device) 10 has an aging testfunction, a problem reproduction function, and the like as theevaluation application for the electronic device 100. The aging testfunction performs a process of providing a pure tone sweep test signaland measuring the response, repeating this process continuously over adesignated number of iterations and analyzing the variation in thefrequency characteristic measured during the process. The problemreproduction function uses a cross-correlation function to identify thesimilarity between two signals, one for a provided sound (test sound)and one for a measured sound, to detect the occurrence of a problem suchas a clip sound or a temporary sound cutoff, a disconnected sound due towireless communication, encoding/decoding conversion of an unintendedsound, or the like.

FIG. 13 illustrates an example of an evaluation application screendisplayed on the display 520. Here, for example, a setting screen 700for setting the test sound in the aging test function is illustrated.The setting screen 700 is activated from a menu in the evaluationapplication of the measurement device 10. The setting screen 700includes a test sound setting unit 701, test sound frequency settingunit 702, test sound duration setting unit 703, test sound amplitudesetting unit 704, measurement start icon 704, and measurement end icon705. The test sound setting unit 701 displays a pull-down or pop-up listincluding, for example, a pure tone, pure tone sweep, multi-sine wave,and variety of WAV files to prompt for user selection. The case of apure tone sweep being set as the test sound is illustrated. Anyfrequency between, for example, 100 Hz to 10 kHz is set in the testsound frequency setting unit 702. Here, a sweep width of 500 Hz to 1.3KHz is set. Furthermore, the test sound duration is set to 10 s. Thetest sound amplitude is set to −10 dB.

Once setting of the test sound setting unit 701, test sound frequencysetting unit 702, test sound duration setting unit 703, and test soundamplitude setting unit 704 is complete, and the measurement start icon704 is operated, then the PC 500 transmits a test start command to thesignal processor 400. Upon receiving the test start command, the signalprocessor 400 causes the test signal generator 497 to generate a testsound based on control by the signal processing controller 470. In theexample in FIG. 13, a test signal corresponding to a pure tone sweep isgenerated. After the addition of a cue signal by the output adjuster498, the generated test signal is provided via the connection cable 511to the external input terminal 105 of the electronic device 100 that istargeted for measurement and held in the holder 70. In this way, thepiezoelectric element attached to the back face of the panel 102 in theelectronic device 100 is driven, the panel 102 vibrates, and vibrationcorresponding to the cue signal and the test signal is sequentiallygenerated. Vibration measurement of the electronic device 100 thenbegins.

The signal processor 400 adjusts sensitivity of the output of thevibration pickup 57 and the microphone 62 with the sensitivity adjuster300, then converts the results to digital signals with the A/D converter410, adjusts the frequency characteristic with the frequencycharacteristic adjuster 420, and subsequently adjusts the phase with thephase adjuster 430 and combines the results with the output combiner440. The output signal of the vibration pickup 57, the phase-adjustedoutput signal of the microphone 62, and the combined signal thereof areprovided to the signal processing controller 470. On the other hand, thesignal combined in the output combiner 440, i.e. the combined signal ofthe vibration transmission component and the air-conducted component, issubjected to frequency analysis by the FFT 451 of the frequency analyzer450.

The signal processing controller 470 detects the cue signal based on theoutput signal of the vibration pickup 57, the phase-adjusted outputsignal of the microphone 62, and the combined signal thereof. Forexample, a pure tone signal of constant sound pressure that can bedetected in the time domain is detected as the cue signal. In responseto the detected cue signal, the signal processing controller 470 thenstores the output of the FFT 451 in the storage 460. The signalprocessing controller 470 outputs the data stored in the storage 460 tothe PC 500, and the PC 500 stores the data in the memory 501. When thepreset duration of the test signal is complete, the signal processingcontroller 470 stops storing the output. The signal processingcontroller 470 corresponds to the “controller” in the presentembodiment.

Alternatively, a configuration may be adopted so that when the cuesignal is a signal detectable in the frequency domain, i.e. a signal atone or a plurality of predetermined frequencies, the signal processingcontroller 470 acquires the output of the FFT 451 and detects the cuesignal having a predetermined frequency component. In response todetection of the cue signal, output of the FFT 451 is then stored in thestorage 460.

The measurement unit 200 repeats the above processing until themeasurement end icon 705 is operated. Alternatively, the setting screen700 may be configured to allow for setting of the number of iterations,with the above processing being repeated until the set number ofiterations is reached.

FIG. 14 illustrates an example of measurement results displayed on thedisplay 520 by the evaluation application of the PC 500. The example inFIG. 14 illustrates a graph comparing frequency characteristics. Thehorizontal axis represents frequency (Hz) and the vertical axisrepresents sound pressure (dB SPL). The dashed line represents thefrequency characteristic of the first iteration, and the solid linerepresents the frequency characteristic for the iteration that has thelargest variation in overall sound pressure. The results of the agingtest on the electronic device 100 are output from the printer 600 asnecessary. The absolute value of the difference between the soundpressure level at the first iteration and the sound pressure levelmeasured the N^(th) iteration (N being one of the number of measurementsstarting at 1) at each frequency may be totaled, and the case of thelargest total value among the N iterations may be treated as the aboveiteration with the largest variation in overall sound pressure whendisplaying, on the display 520, the graph representing the comparisonbetween the first iteration and the iteration with the largestvariation.

The measurement system according to the present embodiment vibrates theelectronic device 100 with a desired test signal, uses the measurementunit 200 to measure the bone-conducted sound and air-conducted soundtransmitted via the ear model unit 50 based on output of the vibrationpickup device (vibration detector) 55 and the microphone device (soundpressure measurement unit) 60, and can evaluate the electronic device100 based on the measurement results. Moreover, at the same time as thevibration level, the sound pressure level can also be measured with themicrophone device 60 via the artificial external ear canal 53 of the earmodel unit 50. The auditory sensation level that combines the vibrationlevel, which corresponds to the amount of vibration transmission to thehuman ear, and the sound pressure level, which corresponds to theair-conducted sound, can thus be measured, allowing for evaluation ofthe electronic device 100 in greater detail. Furthermore, the holder 70can adjust the pressing force on the ear model unit 50 of the electronicdevice 100 and can adjust the contact position, thus allowing for avariety of forms of evaluating the electronic device 100. Accordingly,the electronic device 100 can be evaluated properly, facilitatingspecification management of the electronic device 100.

In the measurement system according to the present embodiment, a testsound such as a WAV file is stored in the test signal storage 496 asminimal sound source information, and a pure tone, pure tone sweep,multi-sine wave, and the like are generated by the test signal generator497, thus economizing on memory resources.

Furthermore, when the electronic device 100 is a mobile phone such as asmartphone, then adopting a configuration to provide the test signal tothe electronic device 100 via wireless communication allows forsimulation of data loss via wireless communication, thereby allowing formore accurate measurement.

When performing wireless communication, however, a difference in timeuntil the test sound is played back on the electronic device 100targeted for measurement occurs as compared to loop-back in which thetest signal is input into the electronic device 100 via the connectioncable 511. This difference in time is due to processing such as encodingby the transmitter 511 t and detection and decoding by the receiver 511r. As a result, in the signal processing controller 470, it becomesdifficult to store and measure the test signal in synchronization withthe start of playback of the test signal and to start measuring. Withrespect to this point, in the present embodiment a cue signal is addedbefore the test signal, and storage begins after detecting the cuesignal. Therefore, it becomes easy to store and measure the test signalin synchronization with the start of playback of the test signal, theprocessing load on the signal processing controller 470 can be reduced,and the storage area of the storage 460 can be used effectively.

Embodiment 4

FIG. 15 illustrates the structure of parts of a measurement systemaccording to Embodiment 4 of the present invention. This measurementsystem 10 has the structure illustrated in FIG. 12, except that the PC500, instead of the signal processor 400, includes the test signaloutput unit 495. Within the PC 500 in the structure in FIG. 15, once atest sound is set on the setting screen 700, the test signal output unit495 responds by outputting the test signal stored in the test signalstorage 496 or the test signal generated by the test signal generator497. Other portions are the same as the structure in FIG. 12.Accordingly, similar effects as those of Embodiment 3 are obtained inthe present embodiment as well, and since the PC 500 has the function ofthe test signal output unit 495, the configuration of the signalprocessor 400 can be simplified.

Embodiment 5

Like the measurement device (measurement system) 10 described inEmbodiment 3 and Embodiment 4, the measurement device (measurementsystem) according to Embodiment 5 of the present invention has an agingtest function and a problem reproduction function as the evaluationapplication for the electronic device 100. As described above, the agingtest function performs a process of providing a pure tone sweep testsignal and measuring the response, repeating this process continuouslyover a designated number of iterations and analyzing the variation inthe frequency characteristic measured during the process.

The problem reproduction function stores, on the memory 501 of the PC500, measurement data for a problem reproduced by providing a particulartest signal, measuring the response, and comparing a cross-correlationcoefficient between the test signal (provided sound) and the measuredsound with a set cross-correlation coefficient threshold. In otherwords, a cross-correlation function is used to identify the similaritybetween two signals, one for a provided sound and one for a measuredsound, and measured data that falls below the set correlationcoefficient threshold is stored in the memory 501 of the PC 500 as datathat reproduces a problem.

With reference to FIG. 10, the following describes the aging testfunction and the problem reproduction function with the measurementdevice according to the present embodiment in greater detail.

Aging Test Function

In the aging test, the variation of the frequency characteristic overalland the variation at a designated, particular frequency are measured.FIG. 16 illustrates an example of an aging test setting screen displayedon the display 520 during the aging test. The aging test setting screen750 is activated from a menu in the evaluation application of themeasurement device 10. The aging test setting screen 750 includes a testsound amplitude setting unit 751, number of iterations setting unit 752,monitored frequency setting unit 753, test start icon 754, and testsuspend icon 755. A pure tone sweep is set as the test sound (testsignal).

The desired amplitude (dB) of the test sound is input into the testsound amplitude setting unit 751. A desired number of iterations, equalto or less than the maximum number of iterations (for example, 10,000)of the pure tone sweep, is input into the number of iterations settingunit 752. The monitored frequency setting unit 753 is provided formeasuring the change in sound pressure in units of frequency. Anyfrequency between, for example, 100 Hz to 10 kHz is input into themonitored frequency setting unit 753. In FIG. 16, three monitoredfrequencies may be input.

The measurement device 10 begins the aging test once input into the testsound amplitude setting unit 751, number of iterations setting unit 752,and monitored frequency setting unit 753 is complete and the test starticon 754 is operated. The following describes an example of operationsby the measurement device 10 for an aging test.

First, once the test start icon 754 on the aging test setting screen 750in FIG. 16 is operated, the PC 500 transmits a test start command forthe aging test to the signal processor 400. Upon receiving the teststart command for the aging test, the signal processor 400 repeatedlygenerates a pure tone sweep with the test signal generator 497 of thetest signal output unit 495, based on control by the signal processingcontroller 470. This generated pure tone sweep is provided via theoutput adjuster 498 and the connection cable 511 to the external inputterminal 105 of the electronic device 100 that is targeted formeasurement and held in the holder 70 (see FIG. 1). In this way, thepiezoelectric element attached to the back face of the panel 102 in theelectronic device 100 is driven, the panel 102 vibrates, and the agingtest of the electronic device 100 begins.

Once the aging test begins, the signal processor 400 adjusts sensitivityof the output of the vibration pickup 57 and the microphone 62 with thesensitivity adjuster 300, then converts the results to digital signalswith the A/D converter 410, adjusts the frequency characteristic withthe frequency characteristic adjuster 420, and subsequently adjusts thephase with the phase adjuster 430 and combines the results with theoutput combiner 440. Subsequently, the signal processor 400 subjects thesignal combined in the output combiner 440, i.e. the combined signal ofthe vibration transmission component and the air-conducted component, tofrequency analysis with the FFT 451 of the frequency analyzer 450 andstores the result in the memory 501 the PC 500.

The measurement unit 200 executes the above processing for one pure tonesweep and then repeats the processing until reaching the set number ofiterations of the pure tone sweep or until the test suspend icon 755 isoperated. Once the set number of iterations is reached, or the test issuspended, the PC 500 displays a comparison graph, on the display 520,of the frequency characteristic during measurement for the firstiteration and the frequency characteristic of the iteration with thelargest variation in overall sound pressure, which indicates the totalvalue of the sound pressure level at each frequency. The absolute valueof the difference between the sound pressure level at the firstiteration and the sound pressure level measured the N^(th) iteration (Nbeing one of the number of measurements starting at 1) at each frequencymay be totaled, and the case of the largest total value among the Niterations may be treated as the above iteration with the largestvariation in overall sound pressure when displaying, on the display 520,the graph representing the comparison between the first iteration andthe iteration with the largest variation.

FIG. 17 illustrates an example of a graph, displayed on the display 520,comparing frequency characteristics. In FIG. 17, the horizontal axisrepresents frequency (Hz) and the vertical axis represents soundpressure (dBSPL). The dashed line represents the frequencycharacteristic of the first iteration, and the solid line represents thefrequency characteristic for the iteration that has the largestvariation in overall sound pressure.

In response to an input operation by the tester, the measurement unit200 selectively displays, on the display 520, an output variation graphat the set monitored frequencies. FIG. 18 illustrates an example of anoutput variation graph, displayed on the display 520, at the monitoredfrequencies. In FIG. 18, the horizontal axis represents the number ofiterations, and the vertical axis represents sound pressure (dBSPL).Note that the measurement results of the frequency closest to the setfrequency among the sequential frequencies in the pure tone sweep aretreated as the measurement results for each monitored frequency. Theresults of the aging test on the electronic device 100 are output fromthe printer 600 as necessary.

With the above aging test, subtle changes in sound when thepiezoelectric element attached to the panel 102 of the electronic device100 is continuously driven and a load is applied to the adhesive statecan be evaluated.

Problem Reproduction Function

The test to reproduce a problem uses a cross-correlation function toidentify the similarity between two signals, one for a provided sound(test sound) and one for a measured sound, in order to detect theoccurrence of a problem such as a clip sound or a temporary soundcutoff, a disconnected sound due to wireless communication,encoding/decoding conversion of an unintended sound, or the like. FIG.19 illustrates an example of a problem reproduction setting screendisplayed on the display 520 during the test to reproduce a problem.Like the above-described aging test setting screen 750, the problemreproduction setting screen 800 is activated from a menu in theevaluation application of the measurement device 10.

The problem reproduction setting screen 800 includes a test sound typesetting unit 801, frequency setting unit 802, test sound amplitudesetting unit 803, test sound duration setting unit 804, number ofiterations setting unit 805, correlation coefficient threshold settingunit 806, test start icon 807, and test suspend icon 808. The test soundtype setting unit 801 selects and sets the test sound to be providedfrom among a pure tone/pure tone sweep/multi-sine/freely chosen WAVfile. The WAV file is read from the test signal storage 496 of the testsignal output unit 495 and output, and therefore the pathname thatindicates the storage location of the WAV file in the test signalstorage 496 is also displayed in the test sound type setting unit 801.

When a pure tone is set in the test sound type setting unit 801, thefrequency thereof is input into the frequency setting unit 802. Thedesired amplitude (dB) of the test sound is input into the test soundamplitude setting unit 803. The playback duration of the test sound tobe provided is input into the test sound duration setting unit 804.Since the cross-correlation of the test sound and a measured sound iscalculated in the test for recreating a problem, a long measurement timeis not appropriate. Accordingly, in the case of a WAV file, a durationof up to 10 s is preferable. A desired number of iterations untilproblem reproduction, equal to or less than the maximum number ofiterations (for example, 10,000), is input into the number of iterationssetting unit 805.

The threshold for the correlation coefficient between the test sound andthe measured sound is input into the correlation coefficient thresholdsetting unit 806. The correlation coefficient varies within a normalrange depending on the existence of wireless communication with theelectronic device 100, the specifications of acoustic processing, andthe like, and may be set to any value in, for example, a range of 0.0 to1.0. The correlation coefficient may, for example, be set to any valuein a range of 0.7 to 1.0 for a strong correlation, 0.4 to 0.7 for amoderate correlation, and 0.0 to 0.4 for nearly no correlation.

The measurement device 10 begins measurement to reproduce a problem onceinput into the test sound type setting unit 801, frequency setting unit802, test sound amplitude setting unit 803, test sound duration settingunit 804, number of iterations setting unit 805, and correlationcoefficient threshold setting unit 806 is complete and the test starticon 807 is operated. The following describes an example of operationsby the measurement device 10 for a test to reproduce a problem.

First, once the test start icon 807 on the problem reproduction settingscreen 800 in FIG. 19 is operated, the PC 500 transmits a test startcommand for the test to reproduce a problem to the signal processor 400.Upon receiving the test start command for the test to reproduce aproblem, the signal processor 400 outputs the set test sound (testsignal) from the test signal output unit 495 based on control by thesignal processing controller 470. For example, when a WAV file is set inthe test sound type setting unit 801, the signal processor 400 reads theset WAV file from the test signal storage 496 and outputs the WAV filevia the output adjuster 498. When a pure tone, pure tone sweep, ormulti-sine is set, the signal processor 400 generates the set test soundwith the test signal generator 497 and outputs the result via the outputadjuster 498. The test sound output from the test signal output unit 495is provided to the PC 500 via the signal processing controller 470.

When using loopback, the test sound output from the measurement unit 200is input into the external input terminal 105 of the electronic device100 targeted for measurement via the connection cable 511, asillustrated in FIG. 10. By contrast, in the case of wirelesscommunication, the test sound is input via the connection cable 511 intoan external input terminal of the counterpart device communicating withthe electronic device 100 targeted for measurement. Therefore, dependingon whether wireless communication is performed, a difference occurs inthe time until the provided test sound is played back by the electronicdevice 100 targeted for measurement.

As in the case of the aging test, the signal processor 400 combines theoutput of the vibration pickup 57 and the microphone 62 in the outputcombiner 440. Subsequently, the signal processor 400 subjects the signalcombined in the output combiner 440, i.e. the combined signal of thevibration transmission component and the air-conducted component, tofrequency analysis with the FFT 451 of the frequency analyzer 450 andprovides the result to the PC 500. Based on the results of frequencyanalysis of the measured sound from the signal processor 400 and theresults of frequency analysis of the provided sound (test sound)processed in the PC 500, the PC 500 computes a cross-correlationfunction between the combined waveform of the vibration transmissioncomponent and the air-conducted component and the waveform of theprovided test sound to calculate the correlation coefficient andcompares the calculated correlation coefficient with the set correlationcoefficient threshold.

As illustrated in FIGS. 20A and B, a time difference t exists betweenthe timing of output of the test sound from the measurement unit 200(FIG. 20A) and the timing of the start of playback of the test sound bythe electronic device 100 targeted for measurement (FIG. 20B). Moreover,this time difference τ varies depending on the conditions of loopback,wireless communication, and the like. Therefore, the PC 500 calculatesthe correlation coefficient between the test sound and the measuredsound starting at the time when the level of the input measured soundexceeds a noise level. A predetermined pilot signal may be inserted atthe head of the measured sound, and the PC 500 may begin calculating thecorrelation coefficient in synchronization with detection of the pilotsignal. In the PC 500, for example in the case of a WAV file, even ifthe analysis length when calculating the correlation coefficient is 10seconds, the correlation coefficient is preferably calculated andcompared with the threshold not for the entire 10 seconds, but rather bydividing into short time periods (such as 0.5 seconds). When the testsound is a pure sound sweep, the correlation is preferably calculatedfor the entire sweep waveform.

When the calculated correlation coefficient is equal to or greater thanthe set correlation coefficient threshold, the PC 500 determines thatthere is no problem and repeats the processing sequence from provisionof the test sound through calculation of the correlation coefficient andcomparison with the threshold, until the set number of iterations isreached. When the calculated correlation coefficient falls below thethreshold before the number of iterations is reached, the PC 500displays the message “problem reproduced” on the display 520 and storesthe waveform data at that time (results of frequency analysis) in thememory 501 of the PC 500. The waveform data stored in the memory 501 isoutput from the printer 600 as necessary. When no problem occurs, i.e.when the calculated correlation coefficient is equal to or greater thanthe threshold, the waveform data is not stored.

Using the above problem reproduction function allows for detection ofnot only a clip sound of the electronic device 100 but also temporarysound cutoff by providing a variety of test sounds and calculating thecorrelation between the provided sound and the measured sound.Furthermore, by providing the test sound to the electronic device 100from the counterpart device by wireless communication, the occurrence ofa problem such as a disconnected sound due to wireless communication,encoding/decoding conversion of an unintended sound, or the like canalso be detected, allowing for detection of a variety of problemsrelated to sound.

Embodiment 6

FIG. 21 schematically illustrates the structure of a measurement systemaccording to Embodiment 6 of the present invention. A measurement device(measurement system) 110 according to the present embodiment has thesame structure as the measurement device (measurement system) 10 of theabove embodiments, as in FIG. 1, except that the structure of anelectronic device mounting portion 120 differs from that of theelectronic device mounting portion 20 illustrated in FIG. 1.Accordingly, the measurement unit 200 illustrated in FIG. 1 is omittedfrom FIG. 21. The electronic device mounting portion 120 is providedwith a human head model 130 and a holder 150 that holds the electronicdevice 100 targeted for measurement. The head model 130 is, for example,HATS, KEMAR, or the like. Artificial ears 131 of the head model 130 aredetachable from the head model 130.

The artificial ear 131 forms the ear model unit and includes, like theear model unit 50 in FIG. 1, an ear model 132 and an artificial externalear canal unit 134, joined to the ear model 132, in which an artificialexternal ear canal 133 is formed, as illustrated by the side view inFIG. 22A of the artificial ear 131 removed from the head model 130. Inthe artificial external ear canal unit 134, like the ear model unit 50in FIG. 1, a vibration pickup device 135 provided with a vibrationtransmission member 56 and a vibration pickup 57 is disposed in theperipheral portion of the opening of the artificial external ear canal133. Accordingly, in the present embodiment, the artificial ear 131 andthe vibration pickup device 135 form the vibration measurement head.FIG. 22A illustrates the right artificial ear 131 as viewed from behind.As illustrated by the side view in FIG. 22B with the artificial ear 131removed, a microphone device 136 provided with a microphone in thecentral portion thereof is disposed on the mounting portion of theartificial ear 131 in the head model 130, and an opening 137 into whichthe vibration pickup 57 of the vibration pickup device 135 fits isformed in the peripheral portion. The microphone device 136 is disposedso as to measure sound pressure of sound propagating through theartificial external ear canal 133 of the artificial ear 131 once theartificial ear 131 is mounted on the head model 130. Like the ear modelunit 50 in Embodiment 1, the microphone device 136 may be disposed onthe artificial ear 131 side. The vibration pickup forming the vibrationpickup device 135 and the microphone forming the microphone device 136are connected to a measurement unit, as in FIG. 1.

A holder 150 is attached to the head model 130 detachably and includes ahead fixing portion 151 for fixing to the head model 130, a support 152that supports the electronic device 100 targeted for measurement, and anarticulated arm 153 connecting the head fixing portion 151 and thesupport 152. The holder 150 is configured so that, like the holder 70 inFIG. 1, the pressing force and contact position, on the artificial ear131, of the electronic device 100 supported by the support 152 can beadjusted via the articulated arm 153.

The measurement device 110 according to the present embodiment achieveseffects similar to those of the measurement device 10 in theabove-described embodiments. Among other effects, in the presentembodiment, the electronic device 100 is evaluated by detachablymounting a vibration measurement head that includes the artificial ear131 for vibration detection and the vibration pickup device 135 to thehuman head model 130, thus allowing for evaluation that conforms moreclosely to the actual form of use by accounting for the effect of thehead.

The present invention is not limited to the above embodiments, and avariety of modifications and changes are allowed. For example, in theabove embodiments, a mobile phone such as a smartphone that vibrateswith the panel 102 as the vibrating body is assumed to be the electronicdevice 100 targeted for measurement, yet an electronic device such as aclamshell phone in which a panel vibrates, the panel being contacted toan ear during a form of use such as talking on the phone, may besimilarly evaluated. Evaluation is not limited to a mobile phone, andother piezoelectric receivers, hearing aids, and the like such as aBlueTooth (registered trademark) headset, speaker, or the like thattransmits sound by vibration transmission may be similarly evaluated. InEmbodiment 6, as in Embodiment 2, a mounting portion may be provided inthe artificial ear 131 to detachably mount the vibration pickup device55 in a predetermined positional relationship.

Furthermore, in the measurement unit 200 illustrated in FIG. 10, thetest signal output unit 495 may be internal to the PC 500, and a testsignal may be provided from the PC 500 to the electronic device 100targeted for measurement and to the counterpart device for theelectronic device 100. The vibration measurement head 40 of theelectronic device mounting portion 20 and the holder 70 that holds theelectronic device 100 are not limited to the above-described structures,and it suffices to adopt a structure that detachably holds theelectronic device 100 and that at least allows for measurement of thevibration component of the vibrating body. When for example measuringdirect vibration of the vibrating body, the ear model unit 50 and themicrophone device 60 may be omitted depending on the characteristicbeing measured for the vibrating body. Furthermore, in accordance withthe structure of the vibration measurement head 40, the FFTs 452 and 453may be omitted, or the FFTs 451 and 453 may be omitted and the agingtest and test to reproduce a problem performed based on the frequencycharacteristic of the vibration transmission component from the FFT 452.

In the above embodiments, the PC 500 is provided separately from thesignal processor 400 in the measurement unit 200, yet the functions ofthe evaluation application executed by the PC 500 may be installed inthe signal processor 400 and the PC 500 omitted. Furthermore, themeasurement unit 200 is not limited to being stand-alone and toconsolidating all of the functions. Rather, a configuration utilizing anetwork system or the cloud, such as the case of distributing themeasurement unit 200 over one or a plurality of PCs or external servers,may of course be adopted.

REFERENCE SIGNS LIST

10: Measurement device (measurement system)

30: Base

40, 41: Vibration measurement head (vibration measurement device)

42: Mounting portion

43: Insertion holder

44: Positioning portion

45: Opening

46: Large-diameter space

50: Ear model unit

51: Ear model

52: Artificial external ear canal unit

53: Artificial external ear canal

54: Support member

55: Vibration pickup device (vibration detector)

56: Vibration transmission member

60: Microphone device (sound pressure measurement unit)

61: Tube member

62: Microphone

70: Holder

71: Support

72: Arm

73: Movement adjuster

75: Signal processor

76: Output unit

100: Electronic device

101: Body

102: Panel (vibrating body)

110: Measurement device (measurement system)

130: Head model

131: Artificial ear

132: Ear model

133: Artificial external ear canal

134: Artificial external ear canal unit

135: Vibration pickup device

136: Microphone device

150: Holder

151: Head fixing portion

152: Support

153: Articulated arm

400: Signal processor

410: A/D converter

420: Frequency characteristic adjuster

430: Phase adjuster

440: Output combiner

450: Frequency analyzer

460: Storage

470: Signal processing controller

480: Acoustic signal output unit

495: Test signal output unit

496: Test signal storage

497: Test signal generator

500: PC (personal computer)

501: Memory

510, 511: Connection cable

The invention claimed is:
 1. A vibration pickup device for measuring anelectronic device that transmits sound to a user via vibrationtransmission by pressing a vibrating body held in a housing against ahuman ear, the vibration pickup device comprising: a plate-shapedvibration transmission member; and a vibration pickup joined to aportion of the vibration transmission member, wherein the vibrationtransmission member is mountable on a peripheral portion of anartificial external ear canal and includes a hole in communication withthe artificial external ear canal, and the artificial external ear canalis formed in an ear model unit modeled after a human ear.
 2. Thevibration pickup device of claim 1, wherein the hole in the vibrationtransmission member has a diameter of 5 mm to 18 mm.
 3. The vibrationpickup device of claim 1, wherein the vibration transmission member isring-shaped.
 4. The vibration pickup device of claim 3, wherein thevibration transmission member has an external diameter 6 mm to 12 mmgreater than a diameter of the hole.
 5. The vibration pickup device ofclaim 1, wherein the vibration pickup comprises a piezoelectricacceleration pickup.
 6. A vibration measurement device for measuring anelectronic device that transmits sound to a user via vibrationtransmission by pressing a vibrating body held in a housing against ahuman ear, the vibration measurement device comprising: an ear modelunit modeled after a human ear; and the vibration pickup device of claim1; wherein in the vibration pickup device, the hole formed in thevibration transmission member is in communication with the artificialexternal ear canal, and the vibration transmission member is mounted ona peripheral portion of the artificial external ear canal formed in theear model unit.
 7. The vibration measurement device of claim 6, whereinthe ear model unit comprises a mounting portion that detachably mountsthe vibration pickup device in a predetermined positional relationship.8. The vibration measurement device of claim 7, wherein the mountingportion comprises an insertion holder that insertably holds thevibration transmission member and a positioning portion that positionsthe vibration pickup with respect to the ear model unit.
 9. Thevibration measurement device of claim 6, further comprising a human headmodel, wherein the ear model unit is an artificial ear forming part ofthe head model and is detachable from the head model.
 10. The vibrationmeasurement device of claim 6, wherein the ear model unit comprises anear model and an artificial external ear canal unit joined to the earmodel, and the artificial external ear canal is formed in the artificialexternal ear canal unit.
 11. The vibration measurement device of claim6, wherein a length of the artificial external ear canal to the holeformed in the vibration transmission member of the vibration pickupdevice is from 8 mm to 30 mm.
 12. The vibration measurement device ofclaim 6, wherein the ear model unit is formed from material conformingto IEC 60318-7.
 13. The vibration measurement device of claim 6, whereinthe ear model unit further comprises a microphone device that measuressound pressure of sound propagating through the artificial external earcanal.
 14. The vibration measurement device of claim 13, wherein themicrophone device comprises a microphone held in a tube member extendingfrom an outer wall of the artificial external ear canal.
 15. Thevibration measurement device of claim 13, wherein the microphone devicecomprises a microphone disposed in a floating state with respect to anouter wall of the artificial external ear canal.